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Method for determining the fill state in a tank utilizing ultrasonic waves and reference surfaces

  • US 10,386,221 B2
  • Filed: 01/13/2017
  • Issued: 08/20/2019
  • Est. Priority Date: 07/14/2014
  • Status: Active Grant
First Claim
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1. A method for determining a level of a liquid in a tank, the method comprising:

  • providing a tank supporting a liquid, the tank defining a tank wall;

    providing an ultrasonic level sensor supported by the tank, the ultrasonic level sensor having a transmitter unit and a receiver unit;

    emitting, from the transmitter unit an ultrasonic wave;

    receiving, at the receiver unit the emitted ultrasonic wave;

    providing a calibration component, the calibration component comprising;

    a spring segment;

    a contact surface pressed fixedly on the tank wall by way of the spring segment; and

    at least two reference surfaces for reflection of the ultrasonic wave, a first reference surface is disposed below a second reference surface;

    providing a controller in communication with the ultrasonic level sensor;

    a) determining, at the controller, a first propagation speed of an ultrasonic wave in the liquid over a first measuring distance from the ultrasonic level sensor to the first reference surface;

    b) determining, at the controller, a second propagation speed of an ultrasonic wave in the liquid over a second measuring distance from the first reference surface to the second reference surface;

    c) measuring, at the controller, a propagation time of an ultrasonic wave from the ultrasonic level sensor to a liquid level of the liquid in the tank;

    d) selecting, at the controller, the first propagation speed or the second propagation speed depending on a first selection criterion and checking, at the controller, the measured propagation speed as a second selection criterion, wherein the second propagation speed is not selected if the measured propagation time lies outside a time interval corresponding to twice the propagation time to the second reference surface and the first propagation speed was selected for a previous iteration of the method; and

    e) computing, at the controller, the level of the liquid with the propagation time measured in step c) and the propagation speed selected in step d).

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